The present invention relates to a separable insertion-type connection for pipes, and, more particularly, to a separable connection in which an end piece of a pipe having an exterior collar can be inserted into an inserting opening of a connecting body, comprising a supporting ring received in the connecting body resting against a wall thereof, an elastic sealing ring arranged behind the supporting ring in an inserting direction, and a holding part configured to reach over the exterior collar and to be fixed with respect to the connecting body such that the pipe is fixable in the inserting opening.
An insertion-type connection in high-pressure pipes is described in German Patent DE-OS 1 475 643. In this construction, the supporting ring has a rectangular cross-section, and is arranged between the exterior collar of the pipe and the elastic sealing ring for supporting the latter. The ring is indisplaceably inserted into the inserting opening of the connecting body, with an annular gap existing between the connecting body and the pipe end piece penetrating the sealing ring.
In sealing rings made of an elastomer, and suitable for extremely low temperatures of, for example, -40.degree. and therefore constructed to be correspondingly soft, the annular gap might result in the destruction of these sealing rings because of a gap extrusion correspondingly high internal pressures (for example, 200 bar). In another insertion-type connection, as described in German Patent DE-AS 1 206 679, this disadvantage was avoided because of the fact that the sealing ring constituting as a sealing lip is molded onto the supporting ring face which faces away from the exterior collar of the pipe and which consists of the same elastic material as the sealing lip.
The thus formed known elastic inserting ring carries out a sealing function as well as a supporting function. The ring is, in turn, arranged in the inserting opening of the connecting body by way of a press fit, on the pipe end piece by way of a sliding fit, and displaceably when subjected to pipe pressure. The inserting ring is forced in the direction of the exterior collar of the pipe, with its interior ring edge facing the exterior collar of the pipe forming a sealing fit for the exterior collar of the pipe constructed as a bead. The resulting prevention of the gap extrusion of the sealing ring (or sealing lip) enclosing the pipe end piece had, however, the disadvantage that, in the event of extreme usage conditions caused by high temperatures and pressures, the inserting ring could creep in the area of the annular gap existing between the wall of the inserting opening and the exterior collar of the pipe.
The present invention has an object of improving a separable insertion-type connection for pipes such that it is distinguished by a long service life of its sealing ring, particularly under extreme usage conditions.
This object has been achieved in accordance with the present invention by providing a sealing lip on the supporting ring face opposite the sealing ring to enclose the pipe end piece in a sealing manner.
The sealing lip in accordance with the present invention is provided on the supporting ring on the side of the sealing ring when acted upon by pressure and is pressed more intensively, irrespective of component tolerances, in a form-locking manner onto the outer circumference of the pipe end piece. As a result, an annular gap which exists between the supporting ring and the pipe end piece is enclosed, and thus a gap extrusion is effectively provided in the event of high pressures and temperature which would result in the destruction of the sealing ring.
A further feature of the present invention offers the advantage that the supporting ring on the sides of the sealing ring also has a sealing lip in the area of its outer edge and both sealing lips end in a common radial plane. Therefore, the sealing ring will be uniformly supported on both sealing lips, in which the sealing lips are uniformly pressed against the circumferential wall or the pipe wall because of the conical construction of the face of the supporting ring.
Another feature of the present invention results in the advantage that a creeping of the supporting ring through the ring gap existing between the opening wall and the exterior collar of the pipe can be prevented without the use of any auxiliary devices, particularly in the event of high temperatures (for example, +120.degree.) and pressures.
A still further aspect of the present invention offers the advantage of a manufacturing of the supporting ring that is particularly simple with respect to manufacturing techniques. In the event of extreme temperatures and pressures, however, this construction requires a measure for preventing a gap extrusion of the supporting ring between the opening wall and the exterior collar of the pipe, which can be achieved advantageously according to the present invention by arranging a closing body between the elastic supporting ring and the exterior collar of the pipe to bridge a radial gap existing between the exterior collar and the opening wall. Preferably, the closing body is a cup-type closing element provided for closing of the gap and closes the annular gap preferably along its entire length. During its manufacturing as a stamped part or a deep-drawn part, the element can be calibrated relative to the diameter of the inserting opening with respect to tolerances such that a reliable gap closure is ensured.
As a result of the configuration of the cup-shaped closing element, by way of its bottom penetrated by the pipe end piece, to reach behind the face of the outer sleeve of the pipe supported on the holding part, which face is opposite or facing the supporting ring, an undisplaceable arrangement of the closing body in the inserting opening is ensured also in the case of very large axial forces directed through the supporting ring onto the closing body.